Wild Ideas: Where are the squirrels?

Answer: In the wild, most are eaten by predators. The few lucky enough to die from natural causes likely expire near a bird feeder at a senior center.

— Richard E. Mallery, “Nuts about Squirrels”

Mark Harkin via Wikimedia Commons

Fewer gray and fox squirrels were spotted in 2014, but are they disappearing?

Early in December, while I was sampling some wine with a couple of friends who are also master naturalists, they asked me where the squirrels had gone. My friends’ home, in western Fauquier County, is surrounded by what is predominantly an oak forest, and they keep a bird feeder loaded year-round. Between the abundant acorn-producing oaks and the full bird feeder, they normally see plenty of squirrels. However, they hadn’t seen any so far in 2014.

A couple of weeks later, Richard Brady, who writes the “Clark Hollow Ramblings” column for the Rappahannock News, emailed me about the lack of squirrels. In his Jan. 1 column, he also bemoaned the fact that last year was the first in a “long, long time” that he hadn’t had some fried squirrel with brown broth gravy and cornbread: “The squirrels seem to have vanished in thin air.”

I also I hadn’t seen any squirrels around my house last year but hadn’t thought much about it. There are few oaks or nut trees in the surrounding forest, so squirrels are generally scarce here. But the mystery of the missing squirrels made me curious, so I contacted naturalist Ron Hughes, who manages several wildlife management areas in Northern Virginia for the Virginia Department of Game and Inland Fisheries (VDGIF).

Ron had also noted the dearth of squirrels: “With all the times I’ve been in the woods hunting deer, I bet I can count on one hand the squirrels I’ve seen.” This was true even in spots where he’d normally see 15 to 20, he said. VDGIF had also been getting a lot of reports from their wildlife biologists, hunters and others about the apparent lack of both gray and fox squirrels in some areas, he added.

So what happened to the squirrels? Noting the complexity of fluctuations in wildlife populations, Ron pointed to several factors that were likely at play, with food availability topping the list. The fall of 2013 saw virtually no acorn production throughout much of Virginia. While acorn production tends to be cyclical in general, that spring the emergence of Brood II of the 17-year cicadas had a big effect on what would probably already have been a low-mast year, he said.

Hardwoods, particularly oaks, are favored hosts of cicadas. The female digs a trench along the tips of young, tender branches in which to deposit her eggs. This basically kills the end of the stem, turning the leaves on it brown — a condition known as “flagging.”

On some trees, only a few stems may be flagged, while other trees take a bigger hit. Young trees can suffer severe damage, even death, from cicadas, but more mature trees usually just reallocate their resources. As VDOF forest health specialist Chris Asaro said in a June 20, 2013 press release, “Although it may be hard for some to believe now, most trees will shed the damaged twigs and replace the lost foliage, appearing normal within a month or two.” This disruption in reproduction doesn’t generally have a long-term impact on the tree, and can even benefit its overall health, but it can limit or eliminate acorn production for that year.

In some areas, nut trees also didn’t produce a lot of mast in 2013, so wildlife that depended on hard mast got a double whammy: “We pretty much had a mast failure in most of the state last year, but it was very significant in the Brood II hatch area. . . . The cicadas hammered the twigs that had the mast being produced on them,” Ron says.

So how much did the rise of the periodical cicadas factor into the low acorn production? “My guess is that it is more pronounced in the areas where the Brood II hatch occurred, rather than statewide,” Ron said, “although we’ve been getting . . . a lot of reports in other areas.”

The effect of Brood II’s emergence was not all bad for wildlife. It offered a nutritional benefit early in 2013, as squirrels as well as other wildlife fed on the hordes of this protein-rich insect, Ron says. That, combined with a heavier mast crop the year before, likely led to higher squirrel reproduction in 2013.

By fall, however, the cicadas were gone, and the acorn crop was a bust. With the crash in food sources, the health of some animals was likely impaired, leading to disease, death or just lower reproduction. However, Ron says, squirrels have another strategy for dealing with such disasters in an area, although they don’t often use it: they migrate to where food is more abundant.

While moving may solve the food problem for some squirrels, it also makes them more vulnerable to other dangers, including predators and cars. Ron says he remembers seeing dead squirrels “all over the roads” last year. The amount of snow we had throughout much of last winter also didn’t help their situation. “Essentially, you had a die off” that caused a “dip” in the squirrel population, he adds.

However, squirrels are good at reproducing, and as populations grow, they are likely to be on the move again and will reappear where acorns had been abundant before — if the trees that produce them are still there.

While acorn crops rebounded in 2014, they were not as big as in the few previous years, says Terry Lasher, a senior area forester with the Virginia Department of Forestry (VDOF). I had written about the 2010 boom in acorn production that fall in this column (Oct. 28). And squirrels may face more mast challenges in the future, Terry warns, thanks to a tiny native insect, the gall wasp, that is doing a lot of damage to several oak species, particularly white oak, which produces the tastiest acorns, according to a National Wildlife Federation blog: “Although acorns from the red group of oaks tend to be higher in fat, protein, calories and fiber than do acorns from white oaks, the astringent quality . . . of red acorns makes them less palatable to wildlife.”

Still, with the acorn and nut crops’ rebounding this fall, squirrel populations are also likely to increase. What occurred last year “was just a natural cycle based on food sources,” Ron says. By next June “we’ll have a lot of squirrels.”

The day after Christmas, my Orlean friends reported in an email that a lone squirrel showed up at their bird feeder. “It was a Christmas miracle,” they said. I’m sure other local residents, particularly those who regularly battle squirrels plundering their bird feeders, will have a different name for it.

Writer, editor, photographer, and passionate nature conservationist living in Rappahannock County, in the Blue Ridge Mountains of Virginia. Two favorite quotes: By E.O. Wilson, who coined the term "biodiversity," "Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction”; by Douglas Adams, “I love deadlines. I love the whooshing sound they make as they pass by.”

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